The urgency for emergency vehicles to reach the location where first responders are needed imposes a need to drive at higher-than-normal speeds and to claim a right of way relative to other vehicles and pedestrians at unpredictable times and under circumstances when conventional rules of the road would favor the other vehicles or pedestrians. Emergency vehicles (police, fire, ambulance, etc.) are therefore equipped with approach warning systems to alert those in the vicinity of the vehicle that they should yield the right of way to the emergency vehicle. Yielding clears a roadway so that the emergency vehicle can pass without delay and without injury to those on the roadway between the emergency vehicle and its destination. The approach warning systems conventionally include sirens and/or lights, which are typically provided as a “light bar” mounted on the roof of a vehicle. A light bar is typically capable of generating a variety of patterns of lights and siren sounds to communicate the degree of urgency with which the vehicle is approaching.